Smooth estimation of human foot motion for zero-velocity-update-aided inertial pedestrian navigation system
Abstract
Purpose
The purpose of this paper is to develop an online smoothing zero-velocity-update (ZUPT) method that helps achieve smooth estimation of human foot motion for the ZUPT-aided inertial pedestrian navigation system.
Design/methodology/approach
The smoothing ZUPT is based on a Rauch–Tung–Striebel (RTS) smoother, using a six-state Kalman filter (KF) as the forward filter. The KF acts as an indirect filter, which allows the sensor measurement error and position error to be excluded from the error state vector, so as to reduce the modeling error and computational cost. A threshold-based strategy is exploited to verify the detected ZUPT periods, with the threshold parameter determined by a clustering algorithm. A quantitative index is proposed to give a smoothness estimate of the position data.
Findings
Experimental results show that the proposed method can improve the smoothness, robustness, efficiency and accuracy of pedestrian navigation.
Research limitations/implications
Because of the chosen smoothing algorithm, a delay no longer than one gait cycle is introduced. Therefore, the proposed method is suitable for applications with soft real-time constraints.
Practical implications
The paper includes implications for the smooth estimation of most types of pedal locomotion that are achieved by legged motion, by using a sole foot-mounted commercial-grade inertial sensor.
Originality/value
This paper helps realize smooth transitions between swing and stance phases, helps enable continuous correction of navigation errors during the whole gait cycle, helps achieve robust detection of gait phases and, more importantly, requires lower computational cost.
Keywords
Acknowledgements
This work was supported by National Natural Science Foundation of China under Grant No.61174027 and No.61473058 and Fundamental Research Funds for the Central Universities (DUT15ZD114). The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group Project No. RGPVPP-281.
Citation
Zhao, H., Wang, Z., Gao, Q., Hassan, M.M. and Alelaiwi, A. (2015), "Smooth estimation of human foot motion for zero-velocity-update-aided inertial pedestrian navigation system", Sensor Review, Vol. 35 No. 4, pp. 389-400. https://doi.org/10.1108/SR-03-2015-0032
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited